1. Field of the Invention
The present invention relates to a lesion area extraction apparatus and method using a radiology report of a medical image. The invention also relates to a computer readable recording medium on which is recorded a program for causing a computer to perform the method.
2. Description of the Related Art
In medical image diagnosis, it is often the case that image reading is performed by a radiologist and the result of the reading is recorded and reported to the attending doctor as a radiology report, in which electronic radiology reports are widely used.
As one of such radiology reports, a report in which a lesion description character is linked to a reference image that includes the lesion area is known. Use of such radiology report allows the attending doctor to click on the lesion description character in the report displayed on a screen to display and observe a corresponding reference image, thereby facilitating the understanding of the radiology report by the attending doctor.
In the image diagnosis, it is also practiced to evaluate the malignancy of a lesion or to decide the treatment policy based on the size or progress of the lesion in the medical image. For such medical diagnosis, it is necessary to accurately extract a lesion area from a medical image. One lesion area extraction method is known as described, for example, in U.S. Patent Application Publication No. 20080044080 in which an arbitrary point is specified by the user in a lesion area of a medical image, a discrimination area is set with reference to the specified point, an evaluation is made as to whether or not each pixel in the discrimination area is a pixel representing the contour of the lesion area, and the contour of the lesion area is determined based on the evaluation result. Here, the evaluation as to whether or not each pixel in the discrimination area is a pixel representing the contour of the lesion area is made by an evaluation function obtained through machine learning of multiple sample images, each including a lesion area with a known contour.
In the mean time, extraction of a contour of a lesion area is conducted, in U.S. Patent Application Publication No. 20080044080, using the same evaluation function regardless of the type of lesion.
Lesion areas, however, differ in characteristics from type to type and the method that extracts all types of lesion areas by the same evaluation function described above does not fully make use of the characteristics of the respective lesion areas, leading to the degradation in extraction performance of a lesion area.
In view of the circumstances described above, it is an object of the present invention to provide a lesion area extraction apparatus and method capable of improving the extraction performance of a lesion area. It is a further object of the present invention to provide a computer readable recording medium on which is recorded a program for causing a computer to perform the method.